Fluid heat exchange apparatus



Sept. 20, 1938. l. 1.. LANGVAND 2,130,351

FLUID HEAT EXCHANGE APPARATUS 7 Filed Feb. 2, 1954 2 Sheets-Sheet 1 INVENTOR Ivar L. Lang-Vand %(3 W ATTORNEY Sept. 20, 1938. 1.1.. LANGVAND 2,130,351

I FLUID HEAT EXCHANGE APPARATUS Filed Feb. 2, 1954 2 Sheets-Sheet 2' Ivar L. Lang vana WW A ORNEY Patented Sept. 20, 1938 UNITED stars PATENT orrics 2,130,351 7 in. near EXCHANGE APPARATUS Application February 2, 1934, Serial No. 709,406

10 Claims.

This invention relates to fluid pressure atparatus, and, more particularly, to apparatus of this type which cause fluids under high pressure to be subjected to heat exchange.

When, in the apparatus mentioned, a fiuid is under high pressure in tubular elements, it is important that the tubular elements and their connections safely withstand the fluid pressure without leaking and that some of said elements be provided with removable parts to permit assembly and repair of the apparatus. High temperatures increase the difiiculties of providing such non-leaking connections. It is an object of the invention to provide such structures which increase the safety factor of the apparatus in which they are installed.

The invention is particularly applicable to the closure of openings in headers at positions opposite the connections of tubes with the headers. Such arrangements are typified in steam boilers, economizers, and other pressure heat exchangers.

Other objects will appear as the accompanying description proceeds.

The invention will be described with reference to the accompanying drawings in which the invention is illustrated as applied to a steam reheater, and in which:

Fig. 1 is a sectional view taken longitudinally of a header illustrating the use of the invention opposite a tube connection.

Fig. 2 is a sectional view of a header taken at a plane-at right angles to the plane of Fig. 1.

Fig. 3 is anelevation showing a part of the header with the hand-hole fitting in operative position.

Fig. 4 is a detail view-indicating the manner in which the hand-hole fitting is inserted in the header.

Fig. 5 is a view similar to Fig. 4 but taken in a plane at right angles to the plane in which Fig. 4 is taken. I

Fig. 6 is a view in the nature of 'a vertical section showing a part of the steam reheater to which the invention is applied.

The illustrated fittings include generally two important structural features. One is that the closure member is provided with an extension which carries the pressure load against a header wall. The second is a welded connection between the closure member and the header, to make the closure pressure tight. The first relieves the second of any substantial stresses due to fiuld pressure.

In the drawings, the header I0 is provided on one side with tube seat openings i2 against the sides of which fluid containing tubes M are adapted to be expanded to form the connection indicated in Figs. 1 and 2. Directly opposite each tube i4 is a hand-hole opening l6 through which the tube M may be removed and replaced. This hand-hole opening also permits the use of an expanding tool to make the connections between the tube i4 and the header l0 pressure tight.

The main portion of the hand-hole fitting I8 is preferably circular and of such a diameter that the entire fitting can be moved through the hand-hole opening as indicated in Figs. 4 and 5. The inner portion of the hand-hole fitting with respect to the center of the header may be considered as a flanged portion presenting diametrically opposite extensions 20 and 22 which bear against the inner wall of the header at positions near its side walls 26 and 26 when the fitting is in its operative position. When the parts are in the positions indicated in Fig. 2 and the fluid is under high pressure-in the apparatus, that pressure will act against the internal area of the hand-hole fitting and will cause the flanged portion of the hand-hole fitting to transmit an outward thrust directly against the inner wall of the header.

In moving the hand-hole fitting to its operative position it is arranged with the extensions and 22 positioned in line with the axis of the hole and the entire fitting is then moved to a position within the header. It is then turned to bring the extensions to an angle of 90 with reference to the axis of the hole and parallel to the base of the hole, then moved axially outwardly in the hole of the header so as to cause the extensions 20 and 22 to contact with the inner side of the header wall. It is then subjected to a considerable force tending to maintain the extensions 20 and 22 in tight contact with the header. This may be accomplished by the insertion of a threaded member into the internally threaded part 28, herein indicated as a nut welded at to the central part of the hand-hole fitting and within its concavity which is presented outwardly of the header.

When the fitting i8 is held in its operative position as indicated in Fig. 2 of the drawings, the extensions 20 and 22 bear upon the portions of the header'wall which are of equal strength or stiffness. In this particular arrangement of ele ments the portions of the wall contacted by extensions 20 and 22 are stifiened by reason of the 1 fact that they are close to the side walls 2d and 26: Between these portions, and circumferentially of the hand-hole there are wall portions of different strength or stifiness. But, in this instance, the last named portions are not contacted by the fitting extensions. Tendencies to distort the hand-hole fitting under conditions 01 high fluid pressures are therefore minimized and the continued integrity of the circumferential weld is promoted.

While the above mentioned pressure is maintained upon the seating flanges of the hand-hole fitting to force the extensions 20 and 22 against the inner wall of the header, a circumferential weld 32 is formed at the outer edge of the fitting. This part of the fitting is preferably bevelled as indicated at 34 so that the main body of weld metal is positioned exteriorly of the outside'face of the header. This construction prevents the leakage of fluid under pressure during the operation of the apparatus and at the same time enables and promotes the removal of the hand-hole fitting by cleaving or chipping away the weld metal without cutting away any of the metal of the header.

Fig. 6 indicates a part of a steam reheater to which the invention may be applied. This reheater consists of a casing 36 through which low pressure steam may be passed longitudinally of the casing. High pressure steam enters the casing through the inlet pipe 38 and proceeds to the header I0 which is indicated as being provided with hand-hole fittings similar to those above described. Nipples 40 connect the primary header ID with secondary headers 42 from which tubes 44 extend to headers similarly arranged at the base of the reheater. Any suitable outlet for the high pressure steam may be arranged at the base of the reheater and connected to a header similar to the primary header l0.

While the invention has been described with reference to the particular structure indicated in the accompanying drawings, it is understood that it is not limited thereto, but is of a scope commensurate with the scope of the subjoined claims.

What is claimed is:

1. In a fluid pressure device, a fluid receiver having a wall formed with an access opening around the perimeter of which parts of the wall are of different stiffness, a closure member fitting within the opening and provided with extensions transmitting pressure created force to parts of said wall of the same stiffness, and means spaced from the extensions and joining the metal of the receiver and said member to make a fluidtight side opposite said opening, a hand-hole fitting I adapted to close the opening, an endless weld strength or stifiness, hand-hole fittings within the openings and provided with extensions contacting with the inner face of the wall and only at positions offset laterally with respect to a line passing through the plurality of aligned access openings and transmitting pressure created force to said wall, and endless welds spaced from the extensions and joining the metal of the header and said fitting to make a fluid tight seal, the pressure outwardly exerted upon said fitting by a contained fluid being transmitted to parts of the header to eifect a fluid tight seal, and flanges on the fittings relieving the weld of any substantial pressure created stress, the flange transmitting the pressure force to the header at a position spaced from the weld and contacting the header wall only at points offset laterally with respect to a line passing through the plurality of aligned access openings.

5. .A hand-hole fitting circular except for its inner portion which presents diametrically opposite overhanging portions connected by curved portions, the outside dimension of the fitting across the overhanging portions being greater than the maximum diameter of the opening to be closed by the fitting, the fitting being bodily insertable through the opening and the overhanging portions having a width which is less than the-diameter of the opening to permit this, the pressure outwardly exerted upon said fitting by a contained fluid being transmitted to parts of the header walls having greater strength or stillness than other parts.

6. In fluid heat exchange apparatus, a tubular header having tube seats formed in a wall thereof, tubes expanded against the tube seats, the wall of the header opposite the tube seats being provided with circular openings positioned directly opposite the tube seats, circular handhole fittings bodily insertable through the circular openings and each including a flanged portion of a length greater than the diameter of its hand-hole opening, each flanged portion being positioned transversely of the header with its overhanging ends contacting the inner surface of the header wall and located close to the opposite header walls which extend from said openings toward the tube seat wall of the header, and a circumferential weld located at the outer edge of each hand-hole opening and tightly joining the fitting and the header.

7. In fluid heat exchange apparatus, a tubular header subject internally'to the high pressure of a fluid to. be heated, said header having tube seats formed in the wall thereof tubes expanded against the tube seats, the wall of the'header opposite the-tube seats being provided with circular openings positioned directly opposite the tube seats, parts of the header wall about each opening having parts of difierent strength or stiffness, circular hand-hole fittings bodily insertable through said openings and each including a flanged portion of a length greater than the diameter of its hand-hole opening, each flanged portion being positioned transversely of the header with its overhanging ends contacting the inner surface of the header wall, and a circumw ferential weld at the outer surface of the header wall and joining the outer end of each fitting to the metal or the header, the pressure outwardly exerted upon said fitting by a contained fluid being transmitted to parts of the header walls having greater strength or stiflness than other parts.

8. In'fluid heat exchange apparatus, a tubular header subject internally to the high pressure of a fluid to be heated and having tube seats formed in a wall thereof, tubes expanded against the tube seats the wall of the header opposite the tube seats being provided with circular openings positioned directly opposite the tube seats, and

hand hole 'fittings bodily insertable through the V circular openings and each including a flanged portion of a length greater than the diameter of its hand-hole opening, each flanged portion being positioned transversely of the header with its overhanging ends contacting the inner surface of the header wall and located close to the opposite header walls which extend toward the tube seat wail of the header, and a circumferential weld at the outer surface of the header wall and joining the outer end of each fitting to the metal of the header.

9. In combination with a pressure vessel formed with an access opening, the parts of the wall of the vessel adjacent the opening having parts of different strength or stiflness, a metallic closure member insertable through the opening to its operative position and having a. part forming a. weld groove with the metal of the exterior surface of the vessel about the opening when in operative position, said member presenting a concavity-opening outwardly of the vessel and having parts which receive the thrusts of pressure created forces and transmit them to the inner part of the wall of the vessel, and a weld seem in the groove to eflect a fluid tight seal, the pressure outwardly exerted upon the closure member by fluid within the vessel being transmitted to parts of the vessel walls having greater strength or stifiness than other parts.

10. In combination with a pressure vessel having an access opening therein, the parts of the wall of the vesml adjacent the opening having parts of different strength or stiffness, of a closure member having an outer part positioned in the opening and an inner part formed with opposite extensions so arranged with reference to the' vessel that pressure upon the closure member is transmitted to parts of the vessel walls having greater strength or stillness than other parts. v

IVAR L. LANGVAND. 

